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EEG waves

Consider a family where mother has passed away leaving 3 children in the protection of father.The father will be the head of family(consider him as alpha), next comes the son who is a college student(Beta), the third child is younger 6 years(theta), the youngest child is an infant(delta).

Alpha wave

Most prominent wave of EEG with frequency of 10-12Hz.

Most marked in the parieto occipital area

Seen in humans who are awake but at rest with mind wandering and eyes closed.

Relation with sleep

Alpha waves (8-11 Hz) are slower and larger. They are associated with a state of relaxation and basically represent thebrain shifting into idling gear, relaxed and disengaged, waiting to respond when needed. If one merely closes his or her eyes and begins picturing something peaceful, in less than half a minute there will be an increase in alpha brainwaves. Alpha is present typically when one feels at ease and calm or in a position to change one’s mind efficiently and effectively in order to accomplish a task.
Sensory Motor Rhythm (12-15 Hz) measured over the sensorimotor cortex are brain waves associated with mental alertness and readiness for action, combined with behavioural stillness.
Beta waves (16 Hz and above) are small, faster brainwaves associated with a state of mental or intellectual activity and outwardly focused concentration. Beta waves are present when one is thinking, problem solving, processing information, or anxious.

Delta brain waves (1-3 Hz) are the slowest, highest amplitude brainwaves, and are present primarily during sleep or when in an empathetic state. Excess delta activity in the awake state is usually indicative of dysfunction.
Theta waves (4-8 Hz) are present when daydreaming or fantasising. At the same time, creativity and intuition are also associated with theta waves. This contrast occurs because theta waves occur at two levels: The lower range of theta (4-5 Hz) basically represents the twilight zone between waking and sleep. It is a profoundly calm, serene, floaty, drifty state. In this range, conscious intellectual activity is not occurring. It is also the range of frequencies produced in excess by children and adults with ADHD.